Search Results (15)

Understanding the processes of organic nitrogen (N) mineralization to ammonium (NH₄⁺) and NH₄⁺ oxidation to nitrate (NO₃⁻), which, together, supply soil inorganic N (the sum of NH₄⁺ and NO₃⁻), is of great significance for guiding the restoration of degraded ecosystems. This study used space-for-time substitution to investigate the dynamic changes in the rates of organic N mineralization (M_Norg) and nitrification (O_NH4) in soil at different vegetation restoration stages. Soil samples were collected from grassland (3–5 years), shrub-grassland (7–8 years), early-stage shrubland (15–20 years), late-stage shrubland (30–35 years), early-stage woodland (45–50 years), and late-stage woodland (70–80 years) in the subtropical karst region of China during the dry (December) and rainy (July) seasons. The M_Norg and O_NH4 were determined using the ¹⁵N labeling technique. The soil microbial community was determined using the phospholipid fatty acid method. Soil organic carbon (SOC), total nitrogen (TN), NH₄⁺, NO₃⁻, and inorganic N contents, as well as the soil moisture content (SMC) were also measured. Our results showed that SOC and TN contents, and the SMC, as well as microbial community abundances increased markedly from grassland to the late-stage shrubland. Especially in the late-stage shrubland, the abundance of the total microbial community, bacteria, fungi, actinomycetes, and AMF in soil was significantly higher than other restoration stages. These results indicate that vegetation restoration significantly increased soil nutrient content and microbial community abundance. From grassland to the late-stage shrubland, the soil NH₄⁺, NO₃⁻, and inorganic N contents increased significantly, and the NH₄⁺:NO₃⁻ ratios changed from greater than 1 to less than 1, indicating that vegetation restoration significantly influenced soil inorganic N content and composition. As restoration progressed, the M_Norg and O_NH4 increased significantly, from 0.04 to 3.01 mg N kg⁻¹ d⁻¹ and 0.35 to 2.48 mg N kg⁻¹ d⁻¹ in the dry season, and from 3.26 to 7.20 mg N kg⁻¹ d⁻¹ and 1.47 to 10.7 mg N kg⁻¹ d⁻¹ in the rainy season. At the same vegetation restoration stage, the M_Norg and O_NH4 in the rainy season were markedly higher than those in the dry season. These results indicate that vegetation restoration and seasonal variations could significantly influence M_Norg and O_NH4. Correlation analysis showed that the increase in M_Norg during vegetation restoration was mainly attributed to the increase in SOC and TN contents, as well as the total microbial community, bacterial, fungal, actinomycetes, and AMF abundances, and that the increase in O_NH4 was mainly attributed to the increase in M_Norg and the decrease in the F: B ratio. Moreover, the M_Norg and O_NH4 showed a strong positive correlation with inorganic N content. This study clarifies that vegetation restoration in karst regions could significantly increase M_Norg and O_NH4 through enhancing soil carbon and N contents, as well as microbial community abundances, thereby increasing the available soil N supply, which could provide a theoretical basis for soil fertility regulation in future rocky desertification management. Full article

Regenerative, pasture-raised layer hen systems create synergistic relationships between the hens, forage, soil, and weather, fostering a sustainable system. However, the influence of these factors on egg nutrient profile and quality may vary by region. This study took place over two years; samples were collected from a farm in Ohio during the first year and a farm in Indiana during the second year. Egg (n = 12) and forage (n = 3) samples were collected monthly from September to December. Fatty acids were quantified using gas chromatography-mass spectrometry, micronutrients were assessed in a commercial laboratory, and carotenoids and polyphenols were analyzed colorimetrically. Ohio eggs had significantly darker yolks (average yolk fan score: 8.5 ± 1.8 vs. 3.9 ± 2.0; p < 0.0001), a higher beta carotene and carotenoid content, and a lower n-6:n-3 fatty acid ratio across the season. Indiana eggs had a lower average total phenolic content (0.07 ± 0.00 mg GAE/g vs. 0.14 ± 0.10 mg GAE/g) and lower average total cholesterol (5.35 ± 2.9 mg/g vs. 10.99 ± 1.54 mg/g). Forage composition and soil parameters varied between farms. Regional variations in forage composition, soil nutrients, and regional weather can significantly influence the nutrient density of eggs produced in sustainable, pasture-raising systems. This research highlights how local environmental factors can shape the nutritional profiles of eggs in different regions. Future studies should explore this relationship in more regions. Full article

The Selçuk district of Izmir is one of the most essential regions in terms of olive oil production. In this study, 60 olive oil samples were obtained from five different locations (ES: Eski Şirince Yolu, KK: Kınalı Köprü, AU: Abu Hayat Üst, AA: Abu Hayat Alt, and DB: Değirmen Boğazı) in the Selçuk region of Izmir during two (2019–2020 and 2020–2021) consecutive cropping seasons. Quality indices (free acidity, peroxide value, p-Anisidine value, TOTOX, and spectral absorption at 232 and 270 nm) and the fatty acid, phenolic, and sterol profiles of the samples were determined to analyze the changes in the composition of Selcuk olive oils according to their growing areas. When the quality criteria were analyzed, it was observed that KK had the lowest FFA (0.11% oleic acid, PV (6.66 meq O₂/kg), p-ANV (11.95 mmol/kg), TOTOX (25.28), and K232 (1.99) values and K270 had the highest value. During the assessment of phenolic profiles, the ES group exhibited the highest concentration of the phenolic compound p-HPEA-EDA (oleocanthal), with a content of 93.58 mg/kg, equivalent to tyrosol. Upon analyzing the fatty acid and sterol composition, it was noted that AU displayed the highest concentration of oleic acid (71.98%) and β-sitosterol (87.65%). PCA analysis illustrated the distinct separation of the samples, revealing significant variations in both sterol and fatty acid methyl ester distributions among oils from different regions. Consequently, it was determined that VOOs originating from the Selçuk region exhibit distinct characteristics based on their geographical locations. Hence, this study holds great promise for the region to realize geographically labeled VOOs. Full article

Dairy products from mountain-origin milk are known for their superior composition and quality. This study aimed to examine changes in composition, nutritional quality, and antioxidant properties of milk from semi-intensively managed goats in mountainous regions during the post-weaning to end-of-lactation period. Bulk tank milk samples from 10 farms were collected bi-weekly in the period from March to September. The farms were situated in regions with an average altitude of 772.20 m above sea level. The results revealed significant variations in milk composition, with fluctuations in fat, protein, lactose, and total solids. Milk yield per doe showed seasonal differences, with the highest yield in April and the lowest in September. Fatty acid composition exhibited changes throughout the sampling period, with variations in polyunsaturated fatty acids. Nutritional indices, such as the atherogenicity index and thrombogenicity index, remained within the recommended values. Antioxidant properties, including total phenolic content, DPPH, FRAP, and ABTS, showed significant differences, with higher values toward the end of the study. Milk pH, electrical conductivity, brix value, and refractive index also exhibited variations, while density and freezing point remained relatively stable. The study provided valuable information that can be used to develop breeding and feeding plans to achieve uniform milk quality in mountainous regions. Full article

Walnut cultivation is expanding into regions where water availability for irrigation is lower than crop evapotranspiration. However, information regarding the responses and adaptations of walnut trees to water deficit remains scarce. In this study, we applied three irrigation levels, 100%, 75%, and 50% of crop evapotranspiration (referred to as T100, T75, and T50, respectively), to Chandler walnut trees over two consecutive seasons. During the second season, we evaluated leaf water-deficit biomarkers, including proline, malondialdehyde, soluble sugars, phenols, and flavonoids, using targeted spectrophotometry. Despite not finding significant differences in biomarker concentrations among the irrigation regimes, we observed variations between different collection times (sprouting, endocarp hardening, and maturity). Furthermore, we assessed the kernel metabolome using untargeted gas chromatography–mass spectrometry, profiling seventy-one metabolites across all samples. Notably, forty-one of these metabolites were identified as members of distinct groups, comprising carbohydrates (n = 11), fatty acids (n = 11), organic acids (n = 9), and amino acids (n = 5). Linear mixed models showed no significant differences between the irrigation regimes. However, in the T50 treatment, multivariate analysis (PCA) revealed a higher concentration of osmotic adjustment metabolites, which are potentially associated with protecting oil biosynthesis under high-temperature and water deficit conditions. Full article

The brackish water clam, Corbicula japonica, acts as an ecosystem engineer in estuaries. To identify its resource-use patterns in the low-turbidity temperate Seomjin River estuary of Korea, we analyzed stable isotope and fatty acid (FA) biomarkers to differentiate allochthonous and autochthonous dietary sources, and examined the effects of clam size, salinity gradient, and season. The δ¹³C and δ¹⁵N values were consistent across the three factors. The δ¹³C values of the clams were similar to those of both riverine- and estuarine-suspended particulate organic matter (R- and E-SPOM), while their δ¹⁵N values were 2–4‰ higher, indicating an equal contribution of both sources to the clam diet. Biogeochemical proxies and FA compositions of SPOM indicate that estuarine phytoplankton significantly contribute to the E-SPOM pool. Moreover, the similarity in FA profiles between Corbicula and E-SPOM indicates that phytoplankton-derived organic matter is the primary source of nutrition for the clam, with minimal impact from growth, salinity gradient, or seasonal changes. Our study suggests that in low-turbidity estuaries with high phytoplankton production, allochthonous organic matter makes a negligible contribution to clam nutrition, compared to high-turbidity estuaries. This finding could provide insights into the variations in the trophic structure of estuarine food webs across diverse regions. Full article

Interactions between above- and below-ground monoculture forest plantation components are critical to tree growth and development. Within the Central Hardwoods Region (CHR), synergistic relationships between tree species and soil microbial community structure and function have received limited research attention. Soil microbes are integral to forest ecosystems as their activities intrinsically promote soil organic matter decomposition, nutrient cycling, and ecosystem functioning. Here, we examined soils from two perfectly aligned stands of black walnut (BW, Juglans nigra L.) and Northern red oak (RO, Quercus rubra L.) trees. Measurements of selected soil chemical properties, microbial community structure using ester-linked fatty acid methyl ester (EL-FAME), and soil enzyme activities (EAs) were used. Analysis of modifications within microbial communities showed a significant positive response to BW based upon soil EAs and microbial indicators, compared to RO. Seasonal comparisons predictably revealed higher microbial activities during summer. Fungi dominated the soil microbial community structure with a fungal/bacterial ratio of 2:1. Gram-positive rather than Gram-negative bacteria or actinomycetes dominated the bacterial community. The activity of the soil enzymes ß-glucosidase and arylsulfatase increased, but ß-glucosaminidase and acid phosphatase decreased. Additionally, acid phosphatase and arbuscular mycorrhizal fungi revealed strong correlations. The differences observed in biological properties, specifically microbial communities and EAs, highlight the varied responses to BW and RO soil biology and subsequent soil ecosystem functions. These results indicate that variations in microbial abundance and soil functions occur throughout the course of an entire year. Full article

Grain protein content (GPC) is a key aspect of grain quality, a major determinant of the flour functional properties and grain nutritional value of bread wheat. Exploiting diverse germplasms to identify genes for improving crop performance and grain nutritional quality is needed to enhance food security. Here, we evaluated GPC in a panel of 255 Triticum aestivum L. accessions from 27 countries. GPC determined in seeds from three consecutive crop seasons varied from 8.6 to 16.4% (11.3% on average). Significant natural phenotypic variation in GPC among genotypes and seasons was detected. The population was evaluated for the presence of the trait-linked single nucleotide polymorphism (SNP) markers via a genome-wide association study (GWAS). GWAS analysis conducted with calculated best linear unbiased estimates (BLUEs) of phenotypic data and 90 K SNP array using the fixed and random model circulating probability unification (FarmCPU) model identified seven significant genomic regions harboring GPC-associated markers on chromosomes 1D, 3A, 3B, 3D, 4B and 5A, of which those on 3A and 3B shared associated SNPs with at least one crop season. The verified SNP–GPC associations provide new promising genomic signals on 3A (SNPs: Excalibur_c13709_2568 and wsnp_Ku_c7811_13387117) and 3B (SNP: BS00062734_51) underlying protein improvement in wheat. Based on the linkage disequilibrium for significant SNPs, the most relevant candidate genes within a 4 Mbp-window included genes encoding a subtilisin-like serine protease; amino acid transporters; transcription factors; proteins with post-translational regulatory functions; metabolic proteins involved in the starch, cellulose and fatty acid biosynthesis; protective and structural proteins, and proteins associated with metal ions transport or homeostasis. The availability of molecular markers within or adjacent to the sequences of the detected candidate genes might assist a breeding strategy based on functional markers to improve genetic gains for GPC and nutritional quality in wheat. Full article

Cork oak (Quercus suber L.) has high economic value given by its sustainable production of cork, and ecological importance in the Mediterranean region. The species is well adapted to the dry climate, namely through the sclerophyllous nature of its leaves with a well-developed cuticle, including cutin and cuticular waxes that contribute to protection against drought. Leaves of cork oaks were collected along one annual cycle, starting from the young leaves in May to the one-year-old leaves in March. Leaf cutin content and chemical composition were determined by transesterification subsequently to the determination of cuticular waxes, and leaf features, and were analyzed along the leaf cycle. Cutin is a major component of the cuticle, representing on average 72.4% of the cutin and cuticular waxes. Cutin amounted to 71.0 g/1000 g of dry leaves, without significant seasonal mass proportion variation, while cutin coverage increased from May to December (429.7 μg/cm² and 575.4 μg/cm², respectively). In contrast, a clear seasonality was found in cuticular wax mass proportion and coverage (18.4 g/1000 g of dry leaves and 113.5 μg/cm² in May, and 28.5 g/1000 g and 235.2 μg/cm² in September). Cutin is a glyceridic polyester composed by long-chain acids, mainly ω-hydroxyacids, followed by fatty acids with a few ω-diacids and alcohols, and by a substantial proportion of aromatics. Cutin composition varied along time with a proportional increase in ω-hydroxyacids (45.8% in May; 50.8% in December), and a significant decrease in aromatics (24.2% in May and 8.5% in March). The cuticle seasonal development in the cork oak contributes to protect the leaves and the trees from the dry summer conditions. Full article

Soil microorganisms and dissolved organic matter (DOM) play vital roles in nutrient cycling and maintaining plant diversity. The aim of this study was to clarify the relationship between DOM component characteristics and microbial community structure in the soil of Larix principis-rupprechtii Mayr. plantations. We quantified the responses of the soil microbial and DOM characteristics to stand age in a plantation forest ecosystem using phospholipid fatty acid (PLFA) analyses, ultraviolet-visible spectroscopy, and fluorescence spectroscopy. Three humic-like components and a fulvic-like component were identified from the soil samples, and humic-like substances were the dominant component of the soil DOM of the stands of different ages. The fluorescence index showed that the sources of soil DOM in the stands of different ages throughout the growth stages may be mostly plant residues, with very little contribution from microbial sources. Furthermore, the results demonstrated that stand age and growth season had a significant effect on the contents of the soil PLFA biomarkers of L. principis-rupprechtii Mayr. Additionally, significantly higher contents of different species of soil PLFA biomarkers were observed in the young forest (17a) than in the sapling forest (7a) and half-mature forest (27a), suggesting that stand age differences in the quality and quantity of larch litter and soil physicochemical characteristics affect the microbial community structure. Redundancy analysis (RDA) showed that changes in the soil DOM quality and components that were driven by growth season and stand age were the major drivers of variations in the soil microbial community structure in the study region. Overall, the seasonal variations in DOM quality and components may contribute to the variability of soil microorganisms, and the soil microbial responses to tree age will depend upon the provisioning of these resources. Full article

Leaves of Pistacia lentiscus were collected from two Algerian sites in the mountains and the littoral of the Tizi-Ouzou region. The harvest was conducted in four consecutive seasons on the same selected set of trees. Essential oils (EOs) were extracted by hydrodistillation; then, they were analyzed by gas chromatography coupled mass spectrometry (GC-MS). Forty-seven constituents could be detected and quantified, including α-pinene (2–13%), β-caryophyllene (8–25%), β-myrcene (0.3–19%), bornyl acetate (0.8–7%), δ-cadinene (3–8%), bisabolol (1–9%), β-pinene (0.9–7%), caryophyllene oxide (4–9%), and α-cadinol (3–11%). Antioxidant (AOx) activities of the EOs were assessed by ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2′-azino-bis (3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) assays. Significant differences in EO composition and AOx activities appeared dependent on the season and the site. Variations of AOx activities were significant for the FRAP and ABTS tests but not for DPPH. Characterization of the leaf fatty acyl (FA) profiles was performed by GC-MS. Variability appeared according to season and altitude. Polyunsaturated fatty acids levels were high (27–55%) at the coldest date and place. The levels of linolenic acyl in the leaves were significantly correlated with bisabolol levels in the EOs (Spearman’s correlation coefficient: 0.818). Such results will be useful for the sustainable local valorization of wild P. lentiscus. These data also open new routes for further studies on terpenoid biosynthesis using correlation networks and fluxomic approaches. Full article

The aim of this study was to examine variations in cow milk composition as a function of breeding system and seasonality. This study was carried out in 16 dairy farms located in the Abruzzo region (Central Italy), equally distributed between farms that adopt grazing in the spring and summer months, and farms where the intensive system is exploited. Milk was sampled in all seasons in each of the farms involved and was analyzed with particular attention given to the quality of the lipid and protein fractions. A lower concentration of saturated fatty acids and an increase in rumenic, vaccenic and oleic acids were registered for milk samples coming from outdoor grazing, in which was also observed the greatest presence of α and β caseins. The opposite result was instead observed for κ casein, which showed the highest values from intensive farming. Evaluations also focused on retinol, which significantly increased in concentration during summer in both breeding systems. The present results suggest positive insights into the role of the outdoor breeding system in improving the main qualitative trait of bovine milk in warm seasons. Full article

The adoption of climate-resilient and resource-use efficient crop species and varieties is a key adaptation action for farmers in the face of climate change. Safflower, an emerging oilseed crop, has been recognized for its high oil quality and its favorable agronomic traits such as drought and cold tolerance, making it particularly suitable to Mediterranean conditions. A 2-year field study was carried out to evaluate the effects of the genotype and growing season on the crop phenology, seed and oil production, macronutrient accumulation and partitioning, and fatty acid composition of spring-sown safflower grown under rainfed conditions. The experiment was conducted during the 2012 and 2013 growing seasons on an alluvial deep loam soil (Typic Xerofluvent) at the Centre for Agri-environmental Research “E. Avanzi” of the University of Pisa (Pisa, Central Italy). Higher seed yield and yield components (plant density, plant height, branching, number of capitula per plant and seeds per capitulum) were found in almost all genotypes when the seeds were sown in mid-March 2012 compared to in late April 2013. More favorable conditions in 2012, i.e., early sowing date, higher precipitation, and quite mild temperatures, led to a better seed and oil yield and greater aboveground biomass and nitrogen uptake, with the highest amounts being removed by straw. Greater seed yield was found to be associated with a greater plant height and a higher number of capitula per plant. Oil content was negatively affected by the higher temperatures and the lower amounts of precipitation that occurred during the 2012 growing season. Seasonal variation in fatty acid composition depended on the genotype. Lower precipitation and higher temperatures during 2013 favored oleic acid content in high linoleic acid genotypes and linoleic acid in medium to high oleic acid genotypes. Among the genotypes, the linoleic-type Sabina and the oleic-type Montola 2000 performed the best in both seasons. The results, besides identifying promising safflower genotypes for spring sowing in the Mediterranean region and for future breeding programs, pointed out the importance of early sowing to contrast unfavorable environmental conditions during seed-filling, thus ensuring higher yields. Full article

The American Heart Association (AHA) recently confirmed common recommendations of one to two fish dishes per week in order to prevent cardiovascular disease (CVD). Nevertheless, the natural fluctuations of lipids and fatty acids (FA) in processed seafood caught little public attention. Moreover, consumers of unprocessed seafood in general do not know how much omega-3 fatty acids (omega-3 FA) within servings they actually ingest. The few studies published until today considering this aspect have been re-evaluated in today’s context. They included four observational studies with canned fatty coldwater fish (mackerel and herring from the same region, season, producer and research group). Their outcomes were similar to those conducted in the following years using supplements. Cans containing seafood (especially fatty coldwater fish) with declared content of omega-3 FA are ready-to-use products. Human studies have shown a higher bioavailability of omega-3 FA by joint uptake of fat. Canned fatty coldwater fish contain omega-3 FA plus plenty of fat in one and the same foodstuff. That suggests a new dietary paradigm with mixed concepts including several sources with declared content of omega-3 FA for reducing the cardiovascular risk and other acknowledged indications. Full article

Climate change is already altering the landscape at high latitudes. Permafrost is thawing, the growing season is starting earlier, and, as a result, certain regions in the Arctic may be subjected to an increased incidence of freeze-thaw events. The potential release of carbon and nutrients from soil microbial cells that have been lysed by freeze-thaw transitions could have significant impacts on the overall carbon balance of arctic ecosystems, and therefore on atmospheric CO₂ concentrations. However, the impact of repeated freezing and thawing with the consequent growth and recrystallization of ice on microbial communities is still not well understood. Soil samples from three distinct sites, representing Canadian geographical low arctic, mid-arctic and high arctic soils were collected from Daring Lake, Alexandra Fjord and Cambridge Bay sampling sites, respectively. Laboratory-based experiments subjected the soils to multiple freeze-thaw cycles for 14 days based on field observations (0 °C to −10 °C for 12 h and −10 °C to 0 °C for 12 h) and the impact on the communities was assessed by phospholipid fatty acid (PLFA) methyl ester analysis and 16S ribosomal RNA gene sequencing. Both data sets indicated differences in composition and relative abundance between the three sites, as expected. However, there was also a strong variation within the two high latitude sites in the effects of the freeze-thaw treatment on individual PLFA and 16S-based phylotypes. These site-based heterogeneities suggest that the impact of climate change on soil microbial communities may not be predictable a priori; minor differential susceptibilities to freeze-thaw stress could lead to a “butterfly effect” as described by chaos theory, resulting in subsequent substantive differences in microbial assemblages. This perspectives article suggests that this is an unwelcome finding since it will make future predictions for the impact of on-going climate change on soil microbial communities in arctic regions all but impossible. Full article